中文摘要：

目的制备^99Tc^m联肼尼克酰胺（HYNIC）-膜联蛋白（Annexin）B1并对其探测细胞凋亡的潜力进行生物学评价。方法应用^99Tc^m间接标记蛋白质的方法，以HYNIC作为双功能螯合剂制备^99Tc^mHYNIC—Annexin B1。采用与活化人血小板结合实验检测^99Tc^m HYNIC—Annexin B1的体外生物活性。采用地塞米松诱导小鼠胸腺凋亡的动物模型和anti—Fas单克隆抗体诱导小鼠肝凋亡的动物模型（均设相应对照组），检测^99Tc^m HYNIC—Annexin B1探测体内细胞凋亡的潜力，并用原位末端标记法（TUNEL）染色证实细胞凋亡。采用配对t检验进行统计学处理。结果间接标记法制备的^99Tc^m HYNIC—Annexin B1具有很高的放化纯（〉96％）和较好的体外稳定性。与活化人血小板的结合实验表明，^99Tc^mHYNIC—Annexin B1具有与磷脂酰丝氨酸（PS）残基结合的生物活性。地塞米松诱导18h后，小鼠胸腺对^99Tc^mHYNIC—Annexin B1的摄取为对照组的3．50倍（t=5．234，P〈0．01）。anti—Fas诱导后2h时，小鼠肝对^99Tc^mHYNIC—Annexin B1的摄取为对照组的2．02倍（t=6．178，P〈0．01）。结论采用^99Tc^m间接标记法制备的^99Tc^mHYNIC—Annexin B1具有很高的放化纯及较好的体外稳定性。^99Tc^m-HYNIC—AnnexinB1具有与PS结合的体外生物活性和探测体内细胞凋亡的潜力，是一种新的细胞凋亡显像剂。

英文摘要：

Objective Annexin B1, a novel Ca^2＋ -dependent phosphatidylserine （PS）-binding protein, has been shown to have a high affinity for PS exposed on the surface of apoptotic cells or activated platelets. The aim of this study was to develop and bioevaluate an Annexin B1 based PS-targeting radiotracer labeled with ^99Tc^m-. Methods Annexin B1 was indirectly labeled with ^99Tc^m- using hydrazinonicotinamide （HYNIC） as a bifunctional chelator agent. Binding assay with human activated platelets was used to evaluate the biological activity of ^99Tc^m-^-HYNIC-Annexin B1 in vitro. The potential of ^99Tc^m--HYNIC-Annexin B1 to detect apoptosis in vivo was evaluated in mice models with dexamethasone-induceed thymus apoptosis and anti-Fas antibody induced liver apoptosis. The paired t-test was used to analyse the data. Results The labeling procedure yielded a compound with radiochemical purity higher than 96% and good in vitro stability. Platelets binding assay indieated that ^99Tc^m--HYNIC-Annexin B1 retained their PS binding activity in vitro. The percentage activity of injection dose per gram of tissue （ % ID/g） of mouse thymus showed a 3.50-fold increase at 18 h after administration of dexamethasone compared with control mice （ t = 5.234, P 〈 0.01 ）. Radionuelide imaging showed a markedly increased uptake of ^99Tc^m--HYNIC-Annexin B1 in the liver of anti-Fas antibody treated mice. The % ID/g of apoptotic murine liver showed a 2.02-fold increase at 2 h after the administration of anti-Fas antibody compared with control mice （ t = 6. 178, P 〈 0. 01 ）. Conclusions These data suggest that ^99Tc^m--HYNIC-Annexin B1 can be prepared with high radiochemical purity and in vitro stability. These data also suggest that ^99Tc^m--HYNIC-Annexin B1 retains its in vitro and in vivo biological activities. It may therefore be useful as a novel radioligand for the noninvasive imaging of PS externalization associated with apoptosis.